
For semiconductors, this represents the energy required to relocate an electron from the valence band maximum (VBM) to the vacuum[1]}. The work function therefore provides a reference frame for comparing binding energies and therefore the strength of chemical bonds. The value of \(W\)  as determined by ab initio calculations is a function of slab thickness. Hence, the thickness of the slab must be chosen to provide a good representation of the surface's electronic properties.
